State and federal health authorities announced record web traffic to online insurance exchanges that, at times, overwhelmed servers on the last day of enrollment before tax penalties take effect.

On the federal exchange, 1.2 million people visited through noon, with more than 125,000 at once during peak times, according to the Centers for Medicare and Medicaid Services, the agency running the online exchange in 36 states. That surge of traffic led to an overload early in the day that stymied application intake, but officials set an unspecified grace period for anyone who tried to complete an application by the deadline but couldn’t. 

The period of intense activity started last week, when officials counted more than 8.7 million visits to the federal exchange,, including more than 2 million over the weekend. In that week CMS’ call center logged more than 2.5 million calls for assistance signing up, about the same number of people who called in all of February.

A number of state exchanges have also extended deadlines, including Maryland and Oregon, which have faced severe technical problems that have prompted state and federal inquiries. Nevada, another state that extended its deadline, was one of several that announced both its highest simultaneous traffic count ever and some technical difficulties handling the surge in traffic. 

But even states that never formally extended the deadline announced they’d consider applicants beyond the March 31 deadline. Washington state, which announced periodic outages during the day, said visitors who weren’t able to complete applications could qualify for “special enrollment on a case-by-case basis,” encouraging customers to contact customer support. Kentucky officials promised to consider anyone who successfully filed an application before the end of March 31. 

California, which has far and away the highest enrollment of any state, surpassed 1.2 million early Monday. Officials there announced that “unprecedented enrollment” was causing the web site to run slowly. 

The 36 federally run insurance exchanges and 14 state-based exchanges offer subsidized private insurance and Medicaid to lower-income applicants. Through February enrollment hit 4.2 million but has ramped up steadily in recent weeks, with Obama administration officials announcing last week that sign-ups had reached 6 million. That’s the estimate from the Congressional Budget Office that was scaled back from 7 million after the disastrous rollout of the federal exchange in October.

Federal officials have said they don’t know how many of the people who signed up have actually paid premiums for the first month, which would make their enrollment official.